I was removing some stuff near the coil and noticed this tube (see photo) hanging down. It is in a big cable bundle on the passenger side of the car. It looks like it slides on the stud (also show) but I can't figure out why a tube would be on this stud. There does not appear to be a hole in the center of the stud and the stud is just attached to the coil mounting bracket.

Do you have any idea what these items are?

Thanks,
Mike

 

I can tell you it doesn't go to that stud. The studs are there for the original spark plug wire looms.

On your car there should be only a couple vacuum lines back there. You've got a line from the MAP to the intake, and another from the HVAC system to the intake. It's probably one of those two.

 

Does your heater system blow out of any vents other than defrost? If only the defrost works, I'm thinking that would be the HVAC system's vacuum source line, especially since you've said that it comes out of the wire loom. It looks like whatever it was connected to (a T in the line running off of the back of the upper intake) had broken before and now it's broken again. I doubt it's for the MAP as the engine would run like crap and throw a code, and the MAP line, IIRC, is not in a wire loom.

 

I believe that goes onto the back of the upper plenum...

 

MAP SENSOR!!!

 

I checked the MAP sensor and back of the intake manifold - both fine. I was driving to work and it occurred to me that it might be the line for the windshield washer. If it is - I feel so stupid. Thanks for all the suggestions. MikeM

 

The washer lines are rubber, not hard plastic.

You aren't looking close enough, three people are telling you were to look. Go to the back of your plenum. There are two fittings. One is a single nipple that goes to your map sensor. Right next to it you'll have a giant T fitting. One side of that T goes to your brake booster. The other side goes a couple of inches and there's a fitting that splits that vacuum signal. One half of that signal is a soft rubber hose that runs all the way to the drivers side of the car, down inside the front fender to the vacuum resevoir ball. The other half of that signal is plumbed to your dash to run all the vacuum operated doors that direct your heating/cooling to the dash or the floor, etc.

Just from looking at your pic, that's the line that goes to the dash. Follow the line from the passengers side of the T to where that line either was disconnected or the plastic valve broke.

 

I have been looking in the right place BUT. I found all the lines and connections as you say, but they don't run the way you describe. The MAP and brake booster are connected as you say. The other line off the T goes to a black splitter. One side of the splitter goes to the fuel pressure regulator and the other side runs along the firewall to the front of the engine and connects to the cruise control servo. I don't recall ever taking the lines off that black splitter but I guess it is possible. We recently rebuilt the engine and we may have switched the lines. If we have the line to the pressure regulator wrong - where does it go?

 

The FPR and the canister purge valve should run to the small port on the throttle body, next to the large port for the canister hose... That HVAC line goes to where the FPR and stuff is currently run, it seems.

 

That is for the EGR solenoid

 

He has the 3-coil electronic EGR valve, which is not vacuum operated...

 

I am getting more confused - unfortunately none of this is in the shop manual.

Here is how the lines run. There are 2 vacuum lines above the throttle plate in the front of plenum - one runs to the air control valve and one runs to the fuel pressure regulator. The line to the FPR has a T with about a 2 foot piece of tubing going to the black T (a damper I think) at the rear of the intake. I think this is wrong.

The back of the plenum where the black damper is located has two lines out of it. One goes to the cruise control. The other is going to the T for the FPR - but this is probably supposed to have the line going to the dashboard on it.

If I connect the dashboard line to the black damper where does the line going to the FPR and the front of the plenum supposed to go??

Your are correct the EGR is electronic.

MikeM

 

That line off of the fuel pressure regulator goes into the valve that is inline of the canister and the fuel tank vapor line... That's what sends the valve the vacuum signal to "purge" the fuel tank vapors, preventing a vacuum inside the tank... At least that's how mine was before all the retrofitting had to be done with the engine that has less vacuum ports than my old one.

 

I'm going to take one more crack at explaining the layout, then you're on your own. Do you have the little vacuum diagram sticker on the bottom of the hood? I really can't remember the specifics of the vacuum lines to the throttle body. I remember that they're formed, and pretty much fall into place.

The fuel pressure regulator runs to the throttlebody. It shouldn't be tied into the rear fittings at all.

The MAP sensor uses the single nipple on the back of the plenum.

The large side of the T on the back of the plenum goes directly to the brake booster.

The small side of the T on the back of the plenum goes to the HVAC system, and the vacuum reservoir. That funny 3 way fitting is a check valve, it keeps vacuum in the reservoir so that there's plenty on hand to drive the vent flappers in the dash.

One leg off the check valve goes to the small side of the T, one goes to the HVAC, and one goes to the reservoir.

Look at this diagram, ignore the incorrect caption, it's a 2.8 or 3.1 in the pic. The connection showing the cap and the little square box with the 2 in it is where the mystery hose goes.

 

OKAY - WE ARE DONE! And I want to thank everyone very, very much. Let me document in case anyone else has this problem which I have been fighting for months.

Yes Drew, there is a small vacuum line diagram under the hood. Can't believe I haven't noticed it. It is a little different than most of the advice, but here goes.

The large tube off the front of the intake manifold goes to the canister. The small line goes to the fuel pressure regulator and at the T, the other line goes to the air control valve. The rear connections are as everyone has stated. BUT that extra line in the bundle with the vacuum line to the dashboard goes the the coolant bypass valve - this car has A/C and the valve diverts hot coolant from the heater core when the A/C is in operation.

After I reconnected everything as diagrammed, the engine was still a little rough and the service light was still on (Code 33). I put the old MAP sensor on (took off the new one) and the service light went off and the engine rans fine both cold and warm.

My son wanted this car running as a birthday present and he got his wish. Once again thank to everyone who provided suggestions on the three threads I started to complete this rebuild. Now it runs fine hot but wants to stall when cold.

Sorry I didn't post sooner but my son reads these posts and I wanted to surprise him on his birthday.

 

Glad to hear it's worked out. I never mentioned the bypass valve because the vacuum line comes a lot further forward then the one in the pic, and doesn't connect to the intake. It didn't really seem pertinent.

If you haven't already, get a can or two of cheap carb cleaner and an old tooth brush. Clean the bejesus out of the throttle body, get the back of the throttle blade and behind the blade in the bore. Remove the IAC valve and clean the passages. Clean all the carbon and oily residue off the valve's pintle and spring, just try not to get cleaner into the motor end of the valve.

The PCV system on the 2.8 and 3.1 tend to dump a bunch of oil and crud in front of the throttle body. The TPI cares do this too, but to a lesser extent. By design there's only a small clearance between the throttle blade and the bore at idle, additional air needed for idle and the idle speed is controlled by the IAC. When the years of oily crud build up in the IAC passages, the pintle starts sticking and the clearance that normally should let air past the throttle blade get plugged up, and the engine won't idle or dies pulling up to stop lights.

 

what if i dont have cruise control but i still have the T near the vacuum ball ?

 

Then it's just capped.

 

thanks